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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/md/linear.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/md/linear.c')
-rw-r--r-- | drivers/md/linear.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c new file mode 100644 index 000000000000..161e9aa87291 --- /dev/null +++ b/drivers/md/linear.c @@ -0,0 +1,343 @@ +/* + linear.c : Multiple Devices driver for Linux + Copyright (C) 1994-96 Marc ZYNGIER + <zyngier@ufr-info-p7.ibp.fr> or + <maz@gloups.fdn.fr> + + Linear mode management functions. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + You should have received a copy of the GNU General Public License + (for example /usr/src/linux/COPYING); if not, write to the Free + Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include <linux/module.h> + +#include <linux/raid/md.h> +#include <linux/slab.h> +#include <linux/raid/linear.h> + +#define MAJOR_NR MD_MAJOR +#define MD_DRIVER +#define MD_PERSONALITY + +/* + * find which device holds a particular offset + */ +static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector) +{ + dev_info_t *hash; + linear_conf_t *conf = mddev_to_conf(mddev); + sector_t block = sector >> 1; + + /* + * sector_div(a,b) returns the remainer and sets a to a/b + */ + (void)sector_div(block, conf->smallest->size); + hash = conf->hash_table[block]; + + while ((sector>>1) >= (hash->size + hash->offset)) + hash++; + return hash; +} + +/** + * linear_mergeable_bvec -- tell bio layer if a two requests can be merged + * @q: request queue + * @bio: the buffer head that's been built up so far + * @biovec: the request that could be merged to it. + * + * Return amount of bytes we can take at this offset + */ +static int linear_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec) +{ + mddev_t *mddev = q->queuedata; + dev_info_t *dev0; + unsigned long maxsectors, bio_sectors = bio->bi_size >> 9; + sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); + + dev0 = which_dev(mddev, sector); + maxsectors = (dev0->size << 1) - (sector - (dev0->offset<<1)); + + if (maxsectors < bio_sectors) + maxsectors = 0; + else + maxsectors -= bio_sectors; + + if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) + return biovec->bv_len; + /* The bytes available at this offset could be really big, + * so we cap at 2^31 to avoid overflow */ + if (maxsectors > (1 << (31-9))) + return 1<<31; + return maxsectors << 9; +} + +static void linear_unplug(request_queue_t *q) +{ + mddev_t *mddev = q->queuedata; + linear_conf_t *conf = mddev_to_conf(mddev); + int i; + + for (i=0; i < mddev->raid_disks; i++) { + request_queue_t *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev); + if (r_queue->unplug_fn) + r_queue->unplug_fn(r_queue); + } +} + +static int linear_issue_flush(request_queue_t *q, struct gendisk *disk, + sector_t *error_sector) +{ + mddev_t *mddev = q->queuedata; + linear_conf_t *conf = mddev_to_conf(mddev); + int i, ret = 0; + + for (i=0; i < mddev->raid_disks && ret == 0; i++) { + struct block_device *bdev = conf->disks[i].rdev->bdev; + request_queue_t *r_queue = bdev_get_queue(bdev); + + if (!r_queue->issue_flush_fn) + ret = -EOPNOTSUPP; + else + ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector); + } + return ret; +} + +static int linear_run (mddev_t *mddev) +{ + linear_conf_t *conf; + dev_info_t **table; + mdk_rdev_t *rdev; + int i, nb_zone, cnt; + sector_t start; + sector_t curr_offset; + struct list_head *tmp; + + conf = kmalloc (sizeof (*conf) + mddev->raid_disks*sizeof(dev_info_t), + GFP_KERNEL); + if (!conf) + goto out; + memset(conf, 0, sizeof(*conf) + mddev->raid_disks*sizeof(dev_info_t)); + mddev->private = conf; + + /* + * Find the smallest device. + */ + + conf->smallest = NULL; + cnt = 0; + mddev->array_size = 0; + + ITERATE_RDEV(mddev,rdev,tmp) { + int j = rdev->raid_disk; + dev_info_t *disk = conf->disks + j; + + if (j < 0 || j > mddev->raid_disks || disk->rdev) { + printk("linear: disk numbering problem. Aborting!\n"); + goto out; + } + + disk->rdev = rdev; + + blk_queue_stack_limits(mddev->queue, + rdev->bdev->bd_disk->queue); + /* as we don't honour merge_bvec_fn, we must never risk + * violating it, so limit ->max_sector to one PAGE, as + * a one page request is never in violation. + */ + if (rdev->bdev->bd_disk->queue->merge_bvec_fn && + mddev->queue->max_sectors > (PAGE_SIZE>>9)) + blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); + + disk->size = rdev->size; + mddev->array_size += rdev->size; + + if (!conf->smallest || (disk->size < conf->smallest->size)) + conf->smallest = disk; + cnt++; + } + if (cnt != mddev->raid_disks) { + printk("linear: not enough drives present. Aborting!\n"); + goto out; + } + + /* + * This code was restructured to work around a gcc-2.95.3 internal + * compiler error. Alter it with care. + */ + { + sector_t sz; + unsigned round; + unsigned long base; + + sz = mddev->array_size; + base = conf->smallest->size; + round = sector_div(sz, base); + nb_zone = conf->nr_zones = sz + (round ? 1 : 0); + } + + conf->hash_table = kmalloc (sizeof (dev_info_t*) * nb_zone, + GFP_KERNEL); + if (!conf->hash_table) + goto out; + + /* + * Here we generate the linear hash table + */ + table = conf->hash_table; + start = 0; + curr_offset = 0; + for (i = 0; i < cnt; i++) { + dev_info_t *disk = conf->disks + i; + + disk->offset = curr_offset; + curr_offset += disk->size; + + /* 'curr_offset' is the end of this disk + * 'start' is the start of table + */ + while (start < curr_offset) { + *table++ = disk; + start += conf->smallest->size; + } + } + if (table-conf->hash_table != nb_zone) + BUG(); + + blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); + mddev->queue->unplug_fn = linear_unplug; + mddev->queue->issue_flush_fn = linear_issue_flush; + return 0; + +out: + if (conf) + kfree(conf); + return 1; +} + +static int linear_stop (mddev_t *mddev) +{ + linear_conf_t *conf = mddev_to_conf(mddev); + + blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ + kfree(conf->hash_table); + kfree(conf); + + return 0; +} + +static int linear_make_request (request_queue_t *q, struct bio *bio) +{ + mddev_t *mddev = q->queuedata; + dev_info_t *tmp_dev; + sector_t block; + + if (bio_data_dir(bio)==WRITE) { + disk_stat_inc(mddev->gendisk, writes); + disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio)); + } else { + disk_stat_inc(mddev->gendisk, reads); + disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio)); + } + + tmp_dev = which_dev(mddev, bio->bi_sector); + block = bio->bi_sector >> 1; + + if (unlikely(block >= (tmp_dev->size + tmp_dev->offset) + || block < tmp_dev->offset)) { + char b[BDEVNAME_SIZE]; + + printk("linear_make_request: Block %llu out of bounds on " + "dev %s size %llu offset %llu\n", + (unsigned long long)block, + bdevname(tmp_dev->rdev->bdev, b), + (unsigned long long)tmp_dev->size, + (unsigned long long)tmp_dev->offset); + bio_io_error(bio, bio->bi_size); + return 0; + } + if (unlikely(bio->bi_sector + (bio->bi_size >> 9) > + (tmp_dev->offset + tmp_dev->size)<<1)) { + /* This bio crosses a device boundary, so we have to + * split it. + */ + struct bio_pair *bp; + bp = bio_split(bio, bio_split_pool, + (bio->bi_sector + (bio->bi_size >> 9) - + (tmp_dev->offset + tmp_dev->size))<<1); + if (linear_make_request(q, &bp->bio1)) + generic_make_request(&bp->bio1); + if (linear_make_request(q, &bp->bio2)) + generic_make_request(&bp->bio2); + bio_pair_release(bp); + return 0; + } + + bio->bi_bdev = tmp_dev->rdev->bdev; + bio->bi_sector = bio->bi_sector - (tmp_dev->offset << 1) + tmp_dev->rdev->data_offset; + + return 1; +} + +static void linear_status (struct seq_file *seq, mddev_t *mddev) +{ + +#undef MD_DEBUG +#ifdef MD_DEBUG + int j; + linear_conf_t *conf = mddev_to_conf(mddev); + sector_t s = 0; + + seq_printf(seq, " "); + for (j = 0; j < conf->nr_zones; j++) + { + char b[BDEVNAME_SIZE]; + s += conf->smallest_size; + seq_printf(seq, "[%s", + bdevname(conf->hash_table[j][0].rdev->bdev,b)); + + while (s > conf->hash_table[j][0].offset + + conf->hash_table[j][0].size) + seq_printf(seq, "/%s] ", + bdevname(conf->hash_table[j][1].rdev->bdev,b)); + else + seq_printf(seq, "] "); + } + seq_printf(seq, "\n"); +#endif + seq_printf(seq, " %dk rounding", mddev->chunk_size/1024); +} + + +static mdk_personality_t linear_personality= +{ + .name = "linear", + .owner = THIS_MODULE, + .make_request = linear_make_request, + .run = linear_run, + .stop = linear_stop, + .status = linear_status, +}; + +static int __init linear_init (void) +{ + return register_md_personality (LINEAR, &linear_personality); +} + +static void linear_exit (void) +{ + unregister_md_personality (LINEAR); +} + + +module_init(linear_init); +module_exit(linear_exit); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("md-personality-1"); /* LINEAR */ |